Definition 7.2 [1]}
A Lie groupoid fibration is a Lie groupoid morphism \(\phi ^1:G\rightarrow G^{\prime }\)  covering a surjective submersion \(\phi ^0:M\rightarrow N\)  with the property that
\(\hat{\phi }:G\rightarrow G^{\prime }\times _NM; g\mapsto (\phi ^1(g),s(g)),\) 
